Acne is generally referred to as acne. 15 year old back acne is associated with abnormal androgen levels and abnormal keratinization of the cells around the hair follicles. When a 15 year old child is in puberty, the sebaceous glands will secrete a large amount of oil when the androgen level in the child’s body increases, and acne will be triggered if no attention is paid to local skin care. At the same time, abnormal keratinization of the cells around the hair follicles on the back will cause the follicle openings to become smaller and blocked, preventing the sebum from being discharged, which will lead to acne. In addition to the above reasons, over-proliferation of Propionibacterium acnes and inflammatory reactions can trigger acne on the back of a 15-year-old child. Application of hormonal drugs, intake of irritating foods, hot environment, and staying up late for a long period of time are among the triggering factors of acne, and even further aggravate acne. When a 15-year-old child has acne on his or her back, it is recommended that he or she go to the hospital in a timely manner and follow the doctor’s instructions for standardized treatment, rather than indiscriminately using medication or scratching with his or her hands. Try to wear cotton, loose clothing to avoid friction and stimulation of foreign objects.